Improvement in smelting gold, silver, and other ores



. K2Sheets--SheetL jw. o. nAv|s.

Smelting Gold. Silver, and other Oras.

No. 133,927.5 Patented Dec.17,1872.

l lofi 2 Sheets--Sheet 2. w. uY nAvls.

Smelting Gold. Silver, and other Oras.

No.133,927. Patented Dec.17,1872.

' Toall aber yitl may cncern.-

1 it known that I, WILLIAM O. DAVIS, of Pittsburgin the county ofAllegheny and State of Pennsylvania, have invented a new andusefullmprovement in the Smelting of Gold, SilvYer, and other Orcs; andI do hereby declare n the following to bea full, clear, and exact de- 'l"scription thereof, reference being had to the accompanying drawing, inwhich- Figure 1 is lafront elevation of a single smelting-chamber j Fig.2 is a sectional elevation through the axis vof the smeltin g chamber;Fig. '3 is a horizontal section through ai w of 15j and Fig. 4 is avertical section through the' center of a smelting -furnace or nest 'ofsmeltingchambers. n In the drawing like letters of reference are used todenote similar parts. y

l In the process of smeltin g the precious met- `als as ordinarilypracticed there is a great loss caused by thel'oxidatien of thosemetals, and great` difficulty,l experienced in the desulphurizin gofthose ores which contain sulphur, and even in those improved furnacesheretofore .nsedwhich are best adapted to overcome these evils theprocess is rendered extremelycostly by the rapid destruction of thesmelting-chambers, owingto the high heat requisite to the conduct of theprocess, together with the introduction of the blast into the smelting-chamber. It is the purpose of my invention greatly lto reduce theloss by oxidation, to provide an effectual and ready mode ofdesulphurization, and to provide la furnace lin which any of the smelt-ving-pots can be easily renewed from timeto time without arresting theprocess in the other yparts of the furnace.

First, as to the waste by oxidation: Ipropose n `in a great measure toobviate this diiiiculty by smelting the precious metals in a furnace sovllnosph'eric air vand gases from the furnace to the melted metals insuch degree as to cause any lserious loss from` that cause; and to thisend I so construct ,my smelting-chamber as to .dispense with the use oftuyeres and blasts `of air which are ordinarily employed; second, in@hier `readily to desulphurize the ores, where this is necessary,I'employ, as a part of the charge, iron sponge, which is metallic ironnearly from oxygen and carbon and in a constructedas top r'event theaccess of the at-j..

PATENT OFFICE.

KWILLIAM o. DAVIS, or PirrsBUnc, PENNSYLVANIA.

' mPR'cvEMENT IN sMEL-rmc com, SILVER, AND oTHER oREs.

A Spcincati'on forming part of Letters Patent No. 133,927, datedDecember 17,1872.

light porous condition, which, when heated awayfrom the presence ofoxygen, has a stron gl affinity for sulphur, and will free the eres ofgold, silver, and leadfrom that substance; and

-such iron sponge may, in some cases, be adl moved and replaced withoutmaterially letting down the heat or stopping the process in the v,otherpots of the set.

A. To enable others skilled in the art to make and use my invention, Iwill proceed to de scribe more in detail the apparatus and process whichI have invented.

In the drawing, Figure 1,*A is the 'smeltin gchamber, built offire-brick or other refractory material. It inay be convenientlylmade ofcylindrical shape. In the center `is the smelting! pot B, made of likesuitable material. It is preferably an upright cylinder having a roundedbottom and a contracted' inverted funnel-V shaped top, furnished at topwith a damper, C, which is ordinarily closed, butis raised whenevernecessary to allow the escape of the sulphurous vapors, gases, &c. Thechamber A is so constructed, as shown in the drawing, as to have aspace, D, all around the sides of the central smelting-pot B, exceptingat the charginglholeE near the top and at the opening for removing theslag and tapping oif-the base bullion, which is at the bottom of thesmeltf ing-pot. The smelting-chamber A is heated by a furnace placedback of the smelting-chamber A, and which may be of any desired con-`struction adapted to furnishing the requisite degree of heat. A Siemensfurnace would answer an excellent purpose. The heated air and gases fromthe furnace enter the smeltingf; chamber at the opening G, at the backand just below the bottoni of the smelting-pot B, and, passing aroundand enveloping the pot, pass away, at the ue H at the bottom of thesmelting-chamber, tothe chimneys I I on each side. Below the kopening Fis the tap-holeJc, which opens into the smelting-pot at its lowest pointso aste drain off all the melted bullion. The

off. These openings are to be kept closed during the process of smeltingby firebrickdoors and stopper, which are removed when necessary. l

The mode of using this smeltin g apparatus is to insert the charge,consisting ofthe ore to be smelted, with the proper flux or fluxes, andiron sponge, if desired, at the charge-hole E, which may then be closedand luted with clay. The slag-hole F is closed by a brick of suitableshape, and the tap-hole K by a plug, while the process of smelting iscarried on. The furnace which supplies the heat may be furnished v. itha blast, if necessary, and dampers to regulate and control the heat; butno air from outside nor gases from the furnace have any access to theinterior of the smelting-pot, and, the heat being uniformly distributedall around the smelting-pot, it is not liable to the rapid destructioncaused bythe blowing in of blasts of air through tuyeres into thesmelting-chamber, as is ordinarily practiced.

As the metal (gold or silver, or silver mixed with lead, as the case maybe) is smelted it vruns down into the bottom of the smeltingpot B, andthe melted slag floats on the top. The atmosphere and gases from thefurnace being excluded, there is little or no oxidation, and thereforevery little if any dross is formed.

At the proper time the brick is withdrawn from the slag-hole F and themolten slag run off.' This brick is speedily replaced so as to allow aslittle air as possible to enter, and then the tap-hole K is opened andthe base bullion drawn oft'.

When sulphur is present in the ores there is added to the charge asuiiicient quantity (depending on the amount of sulphur in the ore) ofiron sponge-an article which is obtain ed in great purity by the processpatented by Thomas S. Blair on May 21,1872. This presence of the ironsponge has the effect of removing the sulphur from its combination withthe ores of gold or silver; and, owing to the highly-sensitive qualityof the sponge when heated, it also absorbs any oxygen which may bepresent in the ore or in the charge, or which may accidentally enter thesmelting-chamber, and thus elfects a great saving in the process ofsmelting the precious metals, producing a much larger percentage ofyield in base bullion.

Fig. 4 represents afurnace for smelting ores in which any convenientnumber of smeltingpots for carrying on my process may be used at thesame time, and by a single re. The furnace is a chamber, circular or ofother suitable form, of brick-work L, covered by a domeshaped roof, andfurnished with a suitable fire-chamber below or at one side, as may bepreferred. As thev construction and arrangement of the fire-bed may bevaried at pleasure, it is not shown in the drawing. Around this circularchamber L is a series of openings at regular intervals, into which areinserted the smelting-pots M M, &c. These pots are placed within thechamber L sufficiently far from its inner wall to have a space allaround the pot, excepting at the projecting parts N and O of the pot,the former of which forms the charging-aperture and the latter theslag-hole. The space in the circular chamber L left for the insertion ofthe pots between the pillars which support the dome-shaped roof isbricked up Y when the pot is set so as to inclose the furnace and retainthe heat. This part of the brickwork is torn down whenever a pot has tobe removed, to be replaced by another. At the top of each pot is acylindrical tunnel-head, l?, which projects out through the roof of thechamber, the space for inserting the pots and the removable brick-workextending to that point or the tuimel-heads may be made separate andinserted through the top of the dome. The top of the tunnel-head P iscovered by a damper, like the smeltng-pot shown in Figs. 1 and 2.

The mode of using these pots is precisely similar to that alreadydescribed. The lire in the furnace is kept up at all times, and thecharging of the several pots is done in rotation, so that the hands maybe kept continually employed, and one set of hands can attend to severalpots.

Whenever one of these pots becomes so far Worn out as to requirerenewal, the brick-work filling the space between the pillars of thefurnace-chamber L is removed, and the old pot is rapidly withdrawn, anda new pot, previously heated in a small detached oven used for thatpurpose, is run into place on an iron carriage, and the hole is rapidlybricked up again. This operation is readily performed, the whole changebeing effected, in ordinary cases, in the space of an hour, more orless.

The apparatus and process hereinbefore described may be applied to thesmelting of copper and lead ores.

On account of the rapidity with which this process can be carried on,and the small percentage of loss, I am enabled to smelt many ores with aremunerative yield which have heretofore been thrown away as wastematerial.

Having ths described my improvement in the smelting of precious metals,what 1 claim as my invention, and desire to secure by Letters Patent,is-- 1. The process of smelting the ores of gold, silver, &c., infurnaces, constructed substantially as hereinbefore described, so as toexclude the atmospheric air and products of combustion of the furnacefrom the interior of the smelting-chamber, substantially as and for thepurposes hereinbefore described. v

2. The combination of iron-sponge in a close smelting-pot with the oreand suitable fluxes as a charge for smelting gold, silver, lead, andother ores, substantially as and for the purposes hereinbeforedescribed.

3. A smelting-chamber consisting of a pot,

eul'strueted 'substantially as hereinbefore deenveloping the pots, asand for the purposes bed, 'so sarto exclude the atmospheric airhereinbefore set forth.

thekproducts of combustion of the fur- In testimony whereof I, the saidWILLIAM from its interior, and surrounded by a O. DAVIS, have hereuntoset my hand.

uiting-chamber, substantially as and for the WILLIAM O. DAVIS. elhereinbefore described. p

l The arrangement of two ormore smeiting- Witnesses: :tgeonstructedsubstantially as described W. N. PAX'ION, fthe preceding claim, in a.furnaeechamber, Gr. H. CHRISTY.

